c.864 - 930
Al-Rasi, born near modern Tehran, was the greatest physician of Islam and the Medieval Ages, and was the undisputable authority on medicine up to Seventeenth century. His original work on smallpox, measles and infectious diseases is still cited in modern textbooks.
Al-Rasi was the first person to introduce the use of alcohol (Arabic Al-Kuhl) for medical purposes.
He was also an expert surgeon and was the first to use opium for anaesthesia. As a director of a hospital he wrote the most complete Arabic medicinal encyclopaedia.
Al-Rasi was also known as a philosopher and he developed the atomic theory of the Greek philosopher Democritus.